Louver grid for lighting fixture



LOUVER GRID FOR LIGHTING FIXTURE 2 Sheets-Sheet 2 Filed Oct. 12, 1966 United States Patent 0 3,381,124 LOUVER GRID FOR LIGHTING FIXTURE Maurice Eisenberg, Chicago, 111., assignor to Solar Light Manufacturing Co., Melrose Park, 111., a corporation of Illinois Filed Oct. 12, 1966, Ser. No. 586,105 21 Claims. (Cl. 240-78) ABSTRACT OF THE DISCLOSURE A lighting baflle of criss-crossed grid structure having a least one wedge-shaped louver. The louver has pairs of aligned spaced openings in its opposed spaced Walls, a plurality of wedge-shaped cross members extending through a cooperating pair of the aligned openings in the louver to form a lattice, and lattice interlock means extending between the side walls of the cross members, thereby establishing a firm and fixed relative position between the louver and the cross members so as to provide a unitary mechanically stable assembly.

This invention relates to louver grids or light control grids of the criss-cross type having intersecting generally wedged-shaped louvers. More particularly, the invention is directed to an improved lattice or grid comprising interlaced and interlocked wedged-shaped louvers defining a criss-cross array constituting a lighting battle. In a prefered embodiment the invention is directed to improved component structural elements for light-directing lattices and to improved inter-coupling means for retaining the structural elements in fixed relative positions. Also included within the scope of the invention are improved methods for fabricating, and improved techniques for assembling the criss-cross grids.

Many types of lighting louvers for fluorescent tubes and the like are known in the prior art. These structures have taken numerous and varied physical forms and many different manufacturing materials, fabrication techniques, and assembly procedures have been used. In some instances the louvers have taken the form of one-piece grids made of glass or of plastic. In other prior art techniques parabolic-walled wed ge-shaped louver grids have been fabricated by injection molding or by casting. Other prior art structures include criss-cross grids fabricated from sheet material by die-cutting blanks and then shaping the blanks to the desired parabolic curvature. In spite of the long time need, and not withstanding the extensive research and development in the relevant art, no completely satisfactory lighting louver of the criss-cross grid type has heretofore been produced. Each prior art physical embodiment has one or more undesirable or objectionable features, and none of the prior art structures has been found completely suitable for the intended purpose.

Glass louvers are undesirably heavy and cumbersome, are costly to produce, and are extremely fragile, posing serious shipping and handling problems. Cast or injection molded plastic lattice structures call for investment in very expensive molds and dies, In addition, the final structures are subject to warpage, shrinkage, and other forms of physical distortion. Prior art baflles constructed of sheet material such as aluminum sheet have required high-cost forming and shaping techniques and have relied upon complex interlocking means, rendering the final assembly of the louvers a tedious and a costly process. The resulting louvers have lacked the rigidity and physical stability required for commercially satisfactory products. It is the aim of this invention to provide efiective solutions to the above and related problems and to eliminate the shortcomings of prior art light control grid assemblies.

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The present invention, therefore, is directed to and has for one of its objects the provision of an improved mechanical structure comprising interlaced and intercoupled criss-cross grid elements forming intersecting generally wedge-shaped louvers.

It is a principal object of the invention to provide a novel mechanical arrangement for interlacing and interlocking louver elements to provide a mechanically sound and physically stable lighting bafl'le.

It is a related very important object of the invention to provide an improved lattice interlock means effective to maintain the criss-cross elements of the grid structure in fixed and firmly held relative positions.

It is another object of the invention to provide a lighting bafile or grid structure in which the louvers generally paralleling the fluorescent lamp or tube are provided with longitudinally or axially spaced pairs of aligned openings in opposed side walls thereof and adapted to receive therethrough generally wedge-shaped cross members or cross louvers.

It is a related object of the invention to provide the openings formed in the longitudinally extending louver with side edge contours which match the curature of the side walls of the cross louvers, so that the side walls lie in substantially contiguous abutment against the openingdefining edges of the longitudinal louver to provide clean intersection lines of interlaced grid elements at the cornering surfaces thereof.

It is a further object of the invention to provide louver and auxiliary structures conveniently fabricated utilizing extrusion techniques, to effect rapid and low cost production.

A related object of the invention is to provide an extruded generally V-shaped cross louver having intergrally formed therewith a pair of opposed, proximately disposed, longitudinally extending inwardly opening and facing Wings, webs, or flanges, C-shaped in cross section and extending inwardly of inner wall surfaces of the louver along a line intermediate upper and lower limits of the louver and paralleling the base thereof.

An important feature of the invention is a wedge-type clip which, in a preferred embodiment, is deformable from an initial configuration in which downwardly extending legs or fingers are spaced for insertion between inwardly facing flanges of a cross louver, to a final configuration in which the fingers are shifted laterally outwardly to engage the flanges and to lock the clip firmly in place to hold the lattice in fixed and rigid assembly.

Still another object of the invention is to provide a longitudinally extending generally wedge-shaped louver of two-piece wall construction in which each of .the two cooperating wall elements is conveniently and effectively fabricated by an extrusion technique, the wall elements including as integral components at the bases thereof mechanical coupling means providing a substantially invisible, aesthetically pleasing juncture of the opposed side walls of the louvers presenting essentially uninterrupted outer Wall surfaces.

Another object of the invention is to provide improved means by which side walls or side panels of the louver grid, or lattice may conveniently and securely be attached to the abutting transversely disposed cross louvers.

Yet a further object of the invention is to provide an improved lattice interlock, wedge, or clip which serves the dual function of bracing the walls of both the longitudinally extending louver and the cross louvers while simultaneously locking the respective louvers in their predetermined positions to provide a rigid and stable mechanical structure.

Other and further features, objects, and advantages of the invention will become apparent from the reading of the following specification taken in conjunction with the drawing in which:

FIGURE 1 is a top plan view of the louver grid or lattice of the invention, incorporating the features thereof;

FIGURE 2 is a bottom plan view of the grid as seen by one standing beneath and looking upwardly at a light fixture utilizing the grid of the invention;

FIGURE 3 is a vertical cross sectional view through a cross louver of the grid and taken substantially on the line 33 of FIGURE 1;

FIGURE 4 is a vertical cross sectional view through a longitudinally extending louver of the grid taken on the line 4-4 of FIGURE 1 and showing the locking clip of the invention in its functional position;

FIGURE 5 is a fragmentary perspective view of the louver grid with portions cut away to illustrate the multiple role of the wedge or clip of the invention;

FIGURE 6 is an enlargement of the detail of the grid circled in FIGURE 1 and showing cross over louvers locked in place by means of the improved clip of the invention;

FIGURE 7 is an enlarged perspective view of the wedge-like clip of the invention; and

FIGURE 8 is an enlargement of the detail of the grid circled in FIGURE 3.

The aims and objects of the invention are accomplished, in a principal preferred embodiment, by providing in a louver lattice construction one or more longitudinally extending parallel louvers, the opposed sides of each louver being formed with aligned cut-outs or openings through which cross louvers or cross members are inserted to provide a grid. The side edges defining the through openings are contoured for correspondence with or to match the configuration of the side walls of the transversely extending louver, and in a preferred embodiment of the invention lattice interlock means are provided to hold the intersecting louvers in relatively fixed positions and in firm assembly. Also included in the scope of the invention are methods for constructing the special component elements thereof. In a preferred technique, these elements are produced by an extrusion process. While aluminum and aluminum and magnesium alloys are preferred structural materials, other compositions lending themselves "to the same general techniques may be used.

Referring now to the drawing in which like reference symbols indicate the same parts throughout the various views, and particularly to FIGURES 1 through 5 there is shown, for the purpose of illustrative disclosure, a preferred embodiment of the louver grid or lattice of the invention, incorporating the teachings thereof. The louver grid includes an elongated louver 24 essentially V-shaped or wedge-shaped in cross section. The opposed walls 28 and 30 of the elongated louver 24 are each provided with longitudinally spaced cut-outs or opening 34 and 34a, corresponding openings in the 0pposed Walls being aligned along axes extending substantially transversely of the length of the louver 24. The openings 34 and 34a, as best seen in FIGURE 4, extend upwardly and outwardly to define a peripheral contour which is generally triangular, the .apex of the triangle being at the base point of the cutout. The side edges and 42 and 40a and 42a defining the lateral bounds of the cut-outs 34 and 34a may conveniently be cut to be substantially parabolic in shape, while the top edge 46 (or 46a) defines a substantially straight horizontally extending line. Also, as seen in the preferred form of the invention-illustrated in 'FIGURE 5, the corners 48 of the triangular cut-outs 34 and 34a are preferably curved or rounded rather than sharp.

Extending through the aligned pairs of the longitudinally spaced openings 34 and 34a in the louver 24 are cross louvers 59, the cross-sectional configuration of these louvers being seen most clearly in FIGURE 5. The cross louvers 50 are generally V-shaped in transverse section (FIGURE 4) and have upwardly and outwardly extending sidewalls 54 and 54a integrally joined at their bases to define an apex or juncture 56 'which is conveniently curved or rounded to ensure a snug fit of the louvers 50 within the corresponding narrow slot portion 58 of the cutouts 3'4 and 34a. Also, as shown in FIGURES 4 and 5, the side walls 54 and 54a of the cross louver 50 are of an upwardly extending linear extent corresponding to the length of the cooperating side edges 40 and 42 defining the lateral bounds of the cut-outs 34 and 34a.

The upwardly and outwardly extending sidewalls 54 and 54a of the cross louver 50 present outwardly facing concave arcuate surfaces of a generally parabolic curvature and corresponding to the curvature of the cooperating arcuate side edges 40 and 40a of the openings 34 and 34a formed in the elongated louver 24, whereby the side walls 54 and 54a of the cross louver 50 are, in the final assembly, in substantially contiguous abutment against the corresponding sides edges 40 and 40a of the elongated louver 24 to provide clean interesection lines at the corners formed by the elongated louver 24 and the cross louvers 50, as seen in FIGURES 2 and 5.

In the preferred form of the invention illustrated, and j as shown in FIGURES 4 and 5, the cross louvers 50 are provided coextensively along upper edges of their opposed side walls 54 and 54a with integrally formed inwardly extending flanges or webs 70 and 70a which generally parallel and lie in substantial abutment against the top edge 46 and 46a of the cut-out slots or openings 34 and 34a. The juncture of the flanges 70 and 70a with their respective walls 54 and 54a are preferably curved rather than sharp, the curvatures corresponding to curvatures 48 at the junctions of opposed side edges 42 and 42a and the top edge 46 and 46a of the cut-outs 34 and 34a to provide a close and aesthetically pleasing fit of the outer wall surfaces of the cross member 50 against the edges outlining the openings 34 and 34a in the elongated louver 24.

Referring further to the preferred structure of the cross louvers 50, and particularly to FIGURE 4, the opposed side walls 54 and 54a carry on their inner surfaces longitudinally along and substantially paralleling the apex 56 of the louver and integrally joined to and formed with the side walls 54 and 54a a pair of opposed inwardly opening and facing flanges or arcuate webs 76 and 76a. The webs 76 and 76a are displaced upwardly of the base juncture 56 of the louver side walls 54 and 54a and define a longitudinally extending through slot or opening 80, the open ing being adapted to receive therewithin mechanical means such as a self-tapping screw 84 by means of which outer sidewalls and 90a bounding the lattice 20 may conveniently be fastened at opposed ends of the cross members or cross louvers 50, as shown in FIGURES 3 and 5. The cross louver 50, with its integral webs 76 and 76a and flanges 70 and 70a is conveniently manufactured by extrusion. 7

As illustrated in FIGURES 3 and 5; arcuate, generally parabolic walls 92 and 92a form the longitudinally extending reflective side walls of the grid 20, completing the lattice structure. The walls 92' and 92a which face respective louver walls 28 and 30 are substantially of the same mechanical form and configuration as the wall 30 of the elongated louver 24, and, accordingly, walls 30 may conveniently be used as louver side walls. The louver Walls 92 and 92a engage within their base slots 94 and 94a the lower marginal portions of the upstanding outer walls 9!) and 90a, while longitudinal edges of horizontally disposed, inwardly extending flanges 96 and 96a integrally formed with the outer walls 90 and 90a abut the louver elements 92 and 92a to retain these firmly in place.

While the inherent resiliency of the louver structures could be relied upon to urge their respective walls outwardly and thus to provide a degree of locking of the respective transversely extending louvers at their crossover positions, in a preferred embodiment of the invention, as shown in FIGURES 3, 4, 5 and 6, special interlock means or locking clips 100 are provided as a positive means for holding or urging the side walls 54 and 54a of the cross louver 50 apart so as to engage firmly and to lock against the side edges 40 and 42 of the cut-outs 34 of the elongated louver 24, as seen in FIGURE 4. Also, in the particular embodiment shown, the clip 100 serves as well to hold apart the side walls 28 and 30 of the elongated louver 24 (FIGURE 6). In addition to holding apart the respective sides 28 and 30 of the transversely disposed V-shaped louvers, the locking clips 100 serve additionally to prevent relative sliding movement of the cross-louver 50 through the elongated louver 24, thus providing a mechanically firm and rigid and physically stable lattice.

Referring now in particular to FIGURE 7, a preferred lattice locking clip 100 finding utility in the practice of this invention is illustrated as constituting a structure which is deformable from an initial position or configuration, as shown in FIGURE 7, to a final louver-locking position, as shown in FIGURE 4. As initially fabricated, preferably by an extrusion process, the locking clip 100 comprises an allochiral assembly bilaterally symmetrical with respect to a center line 104. f a one-piece integral construction, the clip 100 includes .a top wall or saddle 106 vaulted upwardly to reach a peak along a transverse center line 184. A pair of laterally spaced legs or fingers 108 and 108a integrally joined to and extending downwardly of corresponding wall elements 110 and 110a of the saddle 106 complete the structure. As shown, the fingers 108 and 108a are connected to the outwardly extending wall elements 110 and 110a at positions inwardly of the lateral ends of the wall elements. The fingers 108 and 108a may conveniently be crooked 114 and 114:: outwardly to form between each fingers and a corresponding cooperating free end portion 116 and 116a of the vaulted top wall or saddle 106 a laterally opening slot 120 and 120a adapted to receive and seat in the bight portion thereof and therewithin the inwardly extending flanges 70 and 70a of the cross louver 50.

It will be clear from the foregoing description and upon consideration of the drawings that introduction of the flanges 70 and 70a into the slots 120 and 120a may be effected by seating the saddle 106 to bridge the cross louver 54 so that the laterally extreme portions 116 and 116a of the saddle rest upon and are supported by the flanges 70 and 70a and so that the fingers 108 and 108a extend downwardly therebetween (FIGURE 4). Pressure then applied downwardly on the vaulted portion 124 of the saddle 106, preferably along the centerline 104 of the clip deforms the clip causing it to assume the locking configuration illustrated in FIGURE 4. In this final position of the clip 100 the vaulted portion 124 of the saddle has been flattened somewhat causing lateral elongation of the saddle 106 and concurrent arcuate displacement and lateral shifting of the fingers 108 and 108a toward the flanges 70 and 70a. A groove 126 may conveniently be formed along the centerline 104 to facilitate the clip deforming step.

In the finally installed position, the locking clip 100 restrains the sidewalls 54 and 54a against approaching one another and prevents displacement of the walls 54 and 5411 from the side edges of the cut-outs in the elongated louver 24. Conveniently, in this final clip position the preferred lateral spacing or separation of the fingers 108 and 108a is such as to urge the sidewalls 54 and 54a of the cross louver 50 positively against the transversely extending elongated louver 24 to provide clean intersection lines of the walls of the interlaced grid elements.

As shown in FIGURES l and 6, the locking clips 100 are preferably positioned at longitudinally spaced positions along the length of elongated louver 24, these positions being at cross louver intersections so that the clip is locked between both the opposed side walls 28 and 30 and 54 and 54a of the lengthwise extending as well as the cross louvers. As shown, side edges 12% and 128a of the clip parallel one another and extends transversely of the clip centerline 104, the lateral separation or spacing of the side edges 128 and 128a being such as to bring them to bear against inner surfaces 130 and 1300 of the sidewalls 28 and 30 to urge the sidewalls 28 and 30 of the louver 24 outwardly to bear against the upper edge portions or against the top flanges 70 and 70a of the cross louver 50, thereby preventing inward shifting or displacement of the louver sidewalls 28 and 30', to lock the lattice into a firm and stable mechanical grid. From the foregoing description it will be recognized by those skilled in the relevant art that the clips may be fabricated by cutting an extruded form into incremental segments.

In the embodiment of the grid structure, and as seen most clearly in FIGURES 3 and 8, the elongated louver 24 is preferably of a two-piece construction, the side walls 28 and 30 being separate elements coupled to each other at their bases by means of integrally formed joinder means 140. Coupling may be effected by providing the side wall 30 with a reversely turned flange or web 142 extending upwardly of the base 144 to provide an elongated upwardly opening narrow slot 148 coextensive with the base 144 of the side wall 30. The slot 148 slidably receives therewithin a lower free edge portion 152 of the facing side wall 28. In the particular coupling means illustrated, the lower free edge portion 152 of the louver side wall 28 is offset inwardly by means of a connecting cross web 154, the lateral displacement of the lower free edge portion 152 being essentially equal to the thickness of the upstanding flange 142 to ensure a substantially smooth juncture between the upstanding flange 152 and the louver wall 2 8. The outer face of the other louver wall 30 may be provided with a longitudinally extending groove, crease, or marking 15 8 which parallels the line of juncture of the coupling flange 142 with the louver wall 28 so as to provide a complete balance in the appearance of the opposed louver walls and a high degree of visual symmetry. Both walls 28 and 30 and their respective integral coupling means are conveniently fabricated by extrusion processes.

While disclosures of preferred embodiments of the louver grid of the invention and preferred methods for fabricating the structural components of the invention have been provided, it will be apparent to those skilled in the art that numerous modifications, changes, and variations can be made without departing from the essential spirit of the underlying principles of the invention. It is, therefore, desired by the following claims to include in the scope of the invention all such variations and modifications by which substantially the results of this invention may be obtained through the use of substantially the same or equivalent means.

What is claimed is:

1. In a lighting baffle a criss-cross grid structure comprising, in combination;

at least one longitudinally extending louver, V-shaped in cross section,

said louver having pairs of aligned spaced openings tapering upwardly and outwardly and formed in opposed spaced walls of said louver,

a plurality of wedge-shaped cross members comprising elongated upwardly and outwardly extending walls joined along their bases,

each said cross members extending through a cooperating pair of said aligned openings in said louver and disposed transversely of said V-shaped louver to form a lattice therewith,

side edges bounding said openings in said louver being contoured for substantially contiguous abutment against corresponding outer surfaces of said walls of said cross members to provide clean intersection lines of cornering surfaces of said louver and said wedge-shaped cross members, and

lattice interlock means extending between said side walls of said cross members and engaging opposed inner wall surfaces thereof and urging said outer Wall surfaces therefore into contact with said side edges bounding said openings in said louver.

2. The structure as set forth in claim 1 and further comprising lattice interlock means extending between and abutting said opposed facing walls of said louver and maintaining upper edges bounding said openings in said facing walls in contact with opposed upper wall portions of said cross members.

3. The structure as set forth in claim 1 and further comprising inwardly extending substantially horizontal flanges integrally formed at opposed upper edges of said wedge-shaped cross members and extending longitudinally therewith.

4. The structure as set forth in claim 3 and further comprising lattice interlock means positioned between said facing walls of said louver, said interlock means being supported on and keyed to said flanges and maintaining said louver and said cross members in firm and fixed relative positions to provide a unitary mechanically stable assembly.

5. The structure as set forth in claim 4 wherein a top portion of said lattice interlock means supported on said flanges of said cross members comprises a generally horizontal saddle-like plate having opposed side edges extending generally transversely of said members and constituting mechanical stops defining a limit of approach of said walls of said louver toward one another.

6. The structure as set forth in claim 1 wherein each of said louver comprises a pair of separate side walls, and further comprising coupling means at corresponding lower portions of said walls and extending longitudinally therealong for interconnecting said Walls at bases thereof.

7. The structure as set forth in claim 6 wherein said coupling means comprises an upwardly opening generally U-shaped slot formed in and extending longitudinally along a lower edge portion of one wall of said louver and formed by an upturned lower edge of said wall, and a free lower edge portion of the other wall of said louver extending downwardly into said slot to fix said walls against relative lateral movement and separation at their bases.

8. The structure as set forth in claim 7 wherein said free lower edge portion of said other wall of said louver is offset inwardly to define a step extending transversely of said louver, the degree of displacement of said lower edge portion and the width of said step being substantiallly equal to the thickness of said other wall to provide an essentially smooth joint at the base juncture of said walls of said louver.

9. The structure as set forth in claim 1 wherein said cross members are two-walled one-piece assemblies substantially V-shaped in cross section, and further comprising a pair of opposed longitudinally extending inwardly opening and facing webs C-shaped in cross section and integrally formed with respective opposed walls of said cross member at inner surfaces thereof and supported on said opposed walls at positions intermediate upper and lower limits thereof,

said opposed webs defining therebetween a through slot adapted to receive a screw axially therewithin to fasten side walls of said lighting baflle to said cross members of said grid structure.

10. The combination with the structure set forth in claim 3 of lattice interlock means consisting essentially of a clip comprising a generally horizontally extending saddle and spaced legs integrally connected to said saddle and projecting downwardly therefrom,

said clip being positioned to seat and support said saddle on opposed said flanges of said cross member and to present said legs into abutment with respective opposed inwardly facing edge portions of said flanges to retain said clip fixed on said cross member and to preclude shifting of said cross member relative to said louver. v

11. The structure as set forth in claim 10 wherein said clip is supported on said flanges of said cross member at a position between said opposed facing walls of said louver.

12. The structure as set forth in claim 11 wherein side edges of said saddle extending generally transversely of said cross member abut respective said opposed facing walls of said louver to limit approach of said facing walls toward one another.

13. The structure as set forth in claim 3 and further comprising lattice interlock means consisting essentially of a deformable clip comprising:

an upwardly vaulted saddle,

a pair of laterally spaced legs integrally formed with and extending downwardly from said saddle, the

lateral spacing of said legs corresponding essential ly to spacing of inner facing edges of said flanges of said cross member from one another,

said clip being positionable to bridge and seat said saddle upon said flanges with said legs extending downwardly therebetween, and

said clip being deformable in response to pressure applied downwardly against said saddle to flatten said saddle thereby to displace said legs outwardly and into abutment against said flanges to lock said clip onto said cross member.

14. The structure as set forth in claim 13 wherein said legs extending downwardly from said vaulted saddle comprise allochiral hook-like members opening outwardly, whereby deforming pressure applied downwardly against said saddle effects pivotal lateral movement of said hook-like members bringing said members to embrace corresponding edge portions of said opposed flanges of said cross members to lock said clip against both shifting movement relative to said cross members and inadvertent withdrawal therefrom.

15. The structure as set forth in claim 3 and further comprising lattice interlock means consisting essentially of a deformable clip comprising:

a pair of integrally joined outwardly extending allochiral hooks,

valuted bridge means extending between and interconnecting said hooks,

saidl hooks defining laterally opening flange-receiving s ots,

said clip being responsive to pressure applied downwardly upon said valuted bridge means to deform said bridge means toward a flattened configuration to efifect thereby displacement of said hooks outwardly to engage said flanges,

said hooks retaining within said slots thereof opposed said flanges of said cross member whereby said clip locks onto said flanges of said cross member and fixedly secures said cross member against movement relative to said louver to provide a mechanically stable lattice.

16. The structure as set forth in claim 3 and further comprising lattice interlock means consisting essentially of a deformable clip comprising:

a pair of end-connected allochiral hook assemblies disposed symmetrically with respect to a juncture .line therebetween,

joined arms of said assemblies sloping generally downwardly and outwardly of said juncture line to define an inverted flattened V-shaped saddle in cross section,

a finger integrally connected to each said arms at a position intermediate opposed ends thereof and pointing downwardly therefrom,

each said fingers being uncinate to define a hook-like element including a first section connected to said arm and extending generally transversely thereof and a second section integrally formed with said first section and projecting outwardly and downwardly therefrom,

each said hook-like element forming in combination with a free end of the overlying associated arm a laterally openmg flange-receiving slot whereby with said clip positioned so that said saddle bridges and is supported upon opposed said flanges of said cross members and so that said fingers extend downwardly between and adjacent said flanges, pressure applied downwardly on said saddle at said juncture line of said assemblies causes said fingers to pivot outwardly about said juncture line as an axis to engage respective said flanges and to seat free edge portions of said flanges in bight portions of said assemblies forming respective said slots to lock said deformable clip onto said cross member and to obviate shifting of said cross member relative to said louver.

17. The structure as set forth in claim 1 wherein walls of said louver and said cross members define parabolic reflective surfaces.

18. The structure as set forth in claim 9 wherein said cross members comprise one-piece extrusions.

19. The structure as set forth in claim 16 wherein said ciip comprises an incremental length of a unitary extrusion.

20. The structure as set forth in claim 6 wherein said side walls of said louver comprise separate extrusions and wherein said coupling means are integrally formed with respective said side walls at said bases thereof.

21. in the method of fabricating a louver grid for a lighting fixture comprising a lattice of interlaced and interlocked criss-crossed elements providing a mechanically stable and aesthetically pleasing assembly, and including the steps of:

forming a first louver generally V-shaped in cross-section and having longitudinally spaced pairs of aligned openings in opposed walls thereof, said openings being generally triangular in form with upwardly and outwardly extending lateral bounding edges;

forming a plurality of cross louvers also generally V- shaped in cross section, said cross louvers having opposed sidewalls thereof of a contour corresponding to said lateral bounding edges of said first louver, said cross louvers having integrally formed flanges extending inwardly of said opposed sidewalls at upper marginal portions thereof; and

inserting one of said cross louvers to extend transversely through each said pair of aligned openings of said first louver to provide a lattice; the improvement comprising the steps of introducing a clip having an upwardly vaulted saddle ridging said flanges and having integrally formed fingers extend'mg downwardly between said flanges of said cross louvers between said flanges at positions corresponding to positions where said cross louvers pass through said first louver; and

applying downward pressure onto said saddle to deform said clip and to displace said fingers laterally outwardly to engage opposed said flanges to urge said sidewalls of said cross louvers into substantially contiguous abutment against said lateral bounding edges of said openings in said first louver to provide clean intertersection lines of interlaced grid elements of said lattice and to lock said lattice into a unitary stable mechanical structure.

References Cited UNITED STATES PATENTS 2,937,265 5/1960 Blitzer 2409 3,291,978 12/1966 Greenberg et al. 240-78 NGRTON ANSHER, Primary Examiner.

G. M. HOFFMAN, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,381,124 April 30, 1968 Maurice Eisenberg It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 36, "152" should read 142 Column n8 lines 46 and 51, "valuted" each occurrence should read vaulted Signed and sealed this 9th day of September 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward Fletcher, Jr. Attesting Officer Commissioner of Patents 

